Indian police watch while activists in Kolkata block traffic Jan. 3 during a protest against the gang-rape and murder of a 16-year-old girl in Madhyamgram. / Bikas Das, AP

by Mandakini Gahlot , Special for USA TODAY

by Mandakini Gahlot , Special for USA TODAY

NEW DEHLI - A 51-year-old Danish tourist was gang-raped after she got lost and asked a group of men for directions back to her hotel, police said. The case was the latest in a number of highly publicized rapes that have led to a drop in women visiting India.

The attackers used a knife to threaten the woman Tuesday in Paharganj, a backpacker spot popular with foreign tourists in the heart of New Delhi.

They dragged her to an isolated spot, stole her iPad and cash and held her hostage for more than three hours. Six of the men raped her, police said Wednesday. When she got back to her hotel that night, she asked the owner to call the police.

"She was crying a lot and looked like she had been beaten up," said Pushkar Singh, manager of Hotel Amax Inn.

The police detained at least 15 men Wednesday for questioning. All were released.

Eight men have been identified as suspects, said Deputy Police Commissioner Alok Kumar.

"We have set up check posts across the city and are conducting raids. We hope to solve this case soon, over the next few hours," he said.

The woman left for Denmark but told police she would be willing to return to testify in court. She declined to undergo a medical examination, Kumar said.

The problem of sexual violence in India has gained widespread attention since the gang rape and murder of a 23-year-old woman on a moving bus in December 2012. Public fury over the case has led to more stringent laws that doubled prison terms for rape to 20 years.

Since then, there have been several more reports of rapes of foreigners and Indian women that have made headlines. The rapes have sparked major protests among women angry that the punishment for rape isn't more severe.

The violence has had an adverse impact on India's tourism industry. The number of foreign women arriving in India dropped 35% in the first three months of 2013, according to a study published by the Associated Chambers of Commerce and Industry.

Tuesday's rape is the second such attack involving foreigners to be reported from New Delhi in the past two weeks. On Jan. 3, a Polish tourist was allegedly drugged and raped by a taxi driver near a main railway station.

In July, an American tourist was gang-raped in the tourist town of Manali in the state of Himachal Pradesh.

Indian television channel NDTV reported that an 18-year-old German charity worked was raped in southern India on Friday. The woman was traveling by train from Mangalore to Chennai where she was a volunteer with a local charity. She had fallen asleep when she was attacked by one of the passengers. She told police she was too scared to shout and alert the other passengers.

"The young lady took several days to muster courage to report to the police," Seema Aggarwal, the inspector general of police of Chennai, told NDTV. "She only came to us on Monday to file a report. Though it's too late for medical examination, we have handled the case in a very sensitive manner."